1. Field of the Invention
The invention relates to an information recording device for recording time-synchronous information pieces, particularly audio information pieces which are each supplied as continuous and time-synchronous information streams to an input of the recording device at arbitrary intervals between successive pieces. The recording device comprises search means for searching for portions of a track on the record carrier, scanning means for scanning a searched track portion by means of a write head for writing information patterns in the track, said write head being coupled to the input in order to write an information pattern representing the supplied information stream in the scanned track portion, control means adapted to cause the search means to conduct a search operation, prior to writing of an information patterns for an intermediate portion in the track released for recording, said intermediate portion being located between track portions in which an information pattern which is already present is to be retained, said control means being further adapted to cause the write head to record an information pattern representing the supplied information stream in the searched intermediate portion.
The invention also relates to a record carrier comprising a track in which information patterns are recorded which represent time-synchronous information pieces, particularly audio information pieces.
The invention also relates to an information reading device which comprises search means for searching for identified portions of the track on the record carrier, a read head for scanning the information patterns in the searched track portions and for producing and an information stream corresponding to the scanned information patterns, an output for supplying continuous and time-synchronous information streams, said output being coupled to a signal processing circuit.
2. Description of the Related Art
Such a recording device, reading device and record carrier are known from published European Application EP-A-0 275 972. That Application describes a magneto-optical recording device for recording digitized audio information on a reinscribable record carrier in the form of a magneto-optical disc. A table of contents is recorded on the record carrier, which table indicates the start and end addresses of the track portions in which the information patterns for the relevant information pieces, in this case pieces of music, are provided. If the recording of a given piece of music is no longer desired, the address data for the relevant piece of music are removed from the table of contents. The track portions of the relevant piece of music are then released for recording further pieces of music. The recording device is adapted to provides a display, if desired of, the lengths of the released track portions on a display unit. The user may use this information for selecting the location where another piece of music can be recorded. The user should select a released track portion which is sufficiently long for recording the piece of music. Since the length of the selected track portion will always be larger in practice than the required length, a small part of the released track portion will be left after recording. This small part will often be too small for recording further pieces of music, resulting in a poor utilization of the storage capacity of the record carrier. Moreover, when a piece of music is being recorded, the length of the piece of music cannot always be determined in advance. Consequently, when selecting the track portion released for recording, there is a real risk that the selected intermediate portion may not be not long enough.
It is, inter alia, an object of the invention to provide a recording device in which released track portions are selected in a more convenient way.
This object is achieved by a recording device as described in the opening paragraph, which is characterized in that the device comprises an input buffer which is coupled to the input for receiving the information stream to be recorded, and an output which is coupled to an input of the write head for supplying such information stream thereto. The device includes means for detecting, during scanning of an intermediate track portion, when a position in such intermediate portion located proximate to the end thereof is reached means for interrupting, in response to such detection, recording of the information pattern and for supply of the information stream from the input buffer to the write head, and control means for effecting, in response to the aforesaid detection, a search for a further track portion released for recording, resumption supply of the information stream from the input buffer to the write head, and resumption of the recording of the information pattern, storage capacity of the input buffer is sufficient to store the supplied information stream during the search for the next released track portion, the device being further provided with means for storing information indicating in which track portions the information patterns representing the individual information pieces are recorded.
Due to the use of the input buffer there need not be any fixed time relation between the information stream received at the input and the information stream supplied to the output processing circuit. This provides the possibility of temporarily interrupting the recording operation, while the continuous reception of a time-synchronous information piece can be maintained. This renders it possible, at the end of a released intermediate track portion, to make a jump to a subsequent released intermediate portion or to the still unused portion at the end of the track. Consequently the released intermediate portions can be more efficiently utilized. Moreover, the selection of a released intermediate portion for recording of a new piece of information is considerably simpler, because any released intermediate portion can be used up to it capacity.
The information thus recorded can be read by means of a reading device as described above characterized in that the device comprises an output buffer having an input which is coupled to an output of the read head, the output of the output buffer being the output of the device, the device being provided with means for interrupting the information streams at the output buffer on the basis of the control information recorded on the record carrier and for repositioning the scanning to another track portion in which information patterns of a subsequent portion of the information piece to be read are provided after reaching the end of a track portion which includes information patterns of a previous portion of the information piece.
Due to the use of the output buffer there need not be a fixed time relation between the information stream from the signal processing circuit to the output buffer and the information stream at the output of the output buffer. This provides the possibility of making track jumps without this being at the expense of the continuous and time-synchronous supply of an information piece at the output of the reading device.
In this connection it is to be noted that the decoupling of information streams in recording and reading devices is disclosed in published European Application EP-A-0 429 139. In the recording and reading device described in therein the decoupling has for its object to enable information to be recorded at a faster rate than at the rate at which the information is supplied, in order that operation of the tracking and focusing servosystem can be continued with an optimum adjustment. However, the information patterns representing the information pieces are not spread over a number of different intermediate track portions.
The invention is eminently suitable for use in combination with the last-mentioned device, because the provisions rendering the decoupling operation possible can then be used for a dual purpose so that the device is used efficiently.